Abrasive sleeve holder



Aug. 31, 1954 LARSON 2,687,600

' ABRASIVE SLEEVE HOLDER Filed Feb. 23, 1952 Irv/ azar George Allarsanl Patented Aug. 31, 1954- T F F ICE 2 Claims.

This invention relates to a rotatable wheel-like holder for an abrasive sleeve in the form of an endless flexible band. The present improvements are concerned with the holder itself. It is produced mostly, if not entirely, from a resilient material, such as rubber (synthetic, natural, or mixed), with capacity for radial expansion in response to the centrifugal force that arises from rotation. The sleeve fitted around the periphery of the holder is, in consequence, subjected on its inner face to an outward expansion of the holder suflicient to tension the sleeve and secure it fixedly in place.

The present holder utilizes a roller body of rubber-like material formed with a plurality of symmetrically arranged holes which extend therethrough in a direction parallel with its axis. These holes are sized and spaced so as to provide between them solid webs which stretch or compress according to whether the holder is in motion or at rest. When an object is pressed against the sleeve, the holder will tend to yield inwardly, counter to the centrifugally developed force of expansion. By the improved construction disclosed herein, the yieldability of the holder is controlled so as to avoid relatively hard and soft spots at diiferent points in its periphery.

My invention aims to produce a circular holder of the kind described which, although yieldable in response to pressure from the work, provides a substantially constant resistance at all points. It also aims to accomplish this objective by means which is simple and inexpensive and long-lived, and in which there is ample aeration to maintain a relatively cool condition of the holder. The holder itself consists of a one-piece roller, produced by a molding operation or otherwise, so as to involve the minimum of expense in its manufacture.

A holder which attains these various objectives is illustrated in the accompanying drawing where- 1n-- Figure 1 is a view in end elevation of the holder, and

Fig. 2 is a fragmentary view showing localized compression of the holder body in response to pressure applied to the periphery in the direction of the radial arrow.

The holder H is in the form of a roller body having a diameter that is suitable for supporting therearound a sleeve S of predetermined peripheral length. The length of the holder axiswise corresponds generally with the width of a conventional sleeve, perhaps an inch or two. In the holder is a center hole which may be occupied by a bushing B arranged for fitting upon a supporting rotary spindle (not shown) whereby rotation is transmitted to the holder and to the sleeve carried thereby.

The circular holder body is formed of a suitable rubber-like material. This is desirably a relatively soft rubber-natural, synthetic, or otherwise. When rotated, centrifugal force produces a radial expansion of the holder body, tending to enlarge its diameter; when at rest, the holder body contracts again to its normal size.

To control the expansive movements of the holder body so as to maintain a substantially uniform condition of yieldability at every peripheral point is one of the principal objects of this invention. I accomplish this by providing a plurality of holes extending through the holder parallel to its axis. These holes are arranged in circular rows concentrically of the holder axis, those in the inner row designated as 12, being all of one size, whereas those in theouter row, designated as 0, are all of another size. The holes i in the inner row are somewhat larger than those in the outer row, but are fewer in number by onehalf. A herein shown, nine holes 1' in the inner row are provided, and eighteen holes 0 in the outer row, the diameters of the former being greater by about one-third. All of the outer holes 0 are spaced equidistantlly apart as are also the inner holes 2', and each two adjacent outer holes are also spaced the same distance away from one of the inner holes 2' so that all the radial lines rr passing through the centers of the inner holes 2' lie equidistantly between the proximate pairs of outer holes 0.

A holder so constructed is characterized by a first set of webs a which extend radially between the inner holes 2' and by a second set of webs b which extend radially between the outer holes 0. The webs a and b traversed by the radial lines ss define, in effect, spokes which are continuous, whereas the radial lines 7'-7' traverse only the outer webs b, thereby defining, a it were,.spokes which are interrupted by theinner holes 2'. This special arrangement of webs, resulting from inner and outer circular row of holes in one of which rows the number of holes is double that of the other, is responsible for a very efiective performanceof the holder as will now be explained.

In operation,.the.holder is revolved at a normal speed, as 1700 .R. .P. .M., and a piece of work is held in pressure engagement with the'sleeve S which is fitted around the holder to revolve therewith. The outer face of this sleeve carriesa coating of abrasive material which contacts the work. The pressure applied bythe work against the sleeve is often very considerable and also 10- calized, and it is desirable that the holder body yield somewhat in response thereto. This yielding by the present holder body is so controlled that a uniform and even resistance is maintained at every peripheral point. The holder body should have this capacity for such yielding so that the sleeve may tend to flatten somewhat at the point where pressure is applied, particularly when the work face undergoing treatment is relatively fiat.

With pressure exerted against the outer face of the sleeve, the holder will accordingly yield, and, in so doing, parts of its body structure will be displaced somewhat circumferentially. Since the peripheral speed of the sleeve is quite fast, it is manifest that the radial lines 'l'-T and 3-8 follow each other, and others in between, in rapid succession past the point of force application. The inward displacement of the holder body produces an ellipticity of each outer hole with its long axis disposed transversely of the intersecting radial line. The webs b between adjacent pairs of outer holes resist this deformation and are backed up by the inner webs a at certain points, and by other webs c which join the bases of the intermediate webs b with the continuous spokes defined by the next adjacent aligned webs a and b. This displacement of the web structure of the holder at the peripheral point where a force is applied to the sleeve also produces an ellipticity of each inner hole 2'. At each such point a lateral displacement of the adjacent inner webs 11 also takes place.

It is difficult to utilize a circular solid body of resilient material for an abrasive sleeve holder due to excessive weight and temperature generated in use. The provision of holes through the body to reduce this weight and temperature condition has not been satisfactory in the past, due to imbalance of the holder body and weakening of its structure with resulting non-uniformity in its resistance to yielding when a localized pressure is applied to its periphery. By the means herein described, however, these deficiencies of the past have been overcome. This results in part from the provision of inner and outer circular rows of holes, arranged concentrically of each other and of the circular holder body, with the inner holes the larger but only one-half the number of the outer larger holes, the peripheral portion of the holder body being preserved continuous and unbroken; the holes so arranged are spaced apart substantially equidistantly from each other in the same row and from those in the other row; and between adjacent holes in the inner row are stretchable webs which are aligned with other stretchable webs between adjacent pairs of holes in the outer row, the remaining in-between webs between adjacent holes in the outer row being disposed radially oppositely of the holes in the inner row. The body structure so produced is light, well aerated, and deformable in response to a localized pressure at its periphery with a substantially uniform yieldability at every point whereby its abrasive sleeve is enabled to operate more effectively upon the work.

Attention is now called to the provision of a radial slot y which extends outwardly from each outer hole 0 to open out upon the periphery of the holder. These slots promote a lateral or circumferential displacement of the holder body sections therebetween. An inwardly directed radial pressure on the holder will produce a lateral expansion of the adjacent holder body substantially equal in opposite directions due to the space which intervenes between the walls on opposite sides of the slots y. Because each section of the holder body intermediately of adjacent slots :11 is disconnected from the adjacent sections, it is endowed with freedom for movement entirely independently thereof. As a result, the sections of the holder in its peripheral portion have capacity for an increased outward expansion in response to centrifugal force when the holder is rotated, and also an increased inward compression in response to an inwardly directed radial pressure from the work, as the case may be.

I claim:

1. A rotary one-piece expansible sleeve holder of rubber-like material in the form of a roller in which the rubber-like body constitutes at least the major portion of the radius of the roller, the roller body being formed therethrough with a plurality of holes extending between its opposite ends and arranged in at least two concentric circular rows with the holes ineach row arranged in equally circumferentially spaced relation, the cross-sectional area of the holes in the outer row being alike and small in relation to the crosssectional area of the holes in the inner row, and

the number of holes in said inner row being but one-half the number of those in said outer row, the arrangement being such that the webs between adjacent holes in said inner row are aligned with webs between adjacent pairs of holes in said outer row with the remaining in-between webs between adjacent holes in said outer row disposed radially opposite the holes in said inner row, there being formed in the roller body a slot extending radially outwardly from each role in the outer circular row to open out upon the periphery of the roller, thereby to produce a symmetrical section displaceable independently of the adjacent sections laterally in opposite directions, and connected to the roller body by a single radially extending web.

A rotary one-piece expansible sleeve holder of rubber-like material in the form of a roller in which the rubber-like body constitutes at least the major portion of the radius of the roller, the roller body being formed therethrough with a plurality of holes extending between its opposite ends and arranged in at least two concentric circular rows, the holes in the outer row being in equally circumferentially spaced relation, the cross-sectional area of the holes in the outer row being alike and small in relation to the crosssectional area or the holes in the inner row, there being twice as many holes in the outer row as in the inner row and the holes in the inner row being located with their centers on radial lines passing midway between two adjacent holes in the outer row, the holes in the two rows being spaced so that the webs between the holes in the outer row and the periphery of the roller are substantially equal in thickness to the webs between the holes in said outer row and substantially equal in thickness to the webs between the holes in the outer and inner rows, there being formed in the roller body a slot extending radially outwardly from each hole in the outer circular row to open out upon the periphery of the roller, thereby to produce a symmetrical section displaceable independently of the adjacent sections laterally in opposite directions, and connected to the roller body by a single radially extending web.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 965,922 Merigoux Aug. 2, 1910 1,495,083 Krusemark May 20, 1924 2,377,880 Gutsell June 12, 1945 2,548,166 Larson Apr. 10, 1951 

